In order to fix such devices together, a known plug made by Hartwell Corp., U.S.A., comprises a socket and a plunger that may be inserted into the socket. In this arrangement, the socket is inserted, with a degree of initial tension, into a first through-opening in the form of a hole within a lower device, wherein the socket is longer, by a projecting section, than the depth of the hole. The second device, approximately in the form of a movable plate, with a further through opening, is placed over the first through-opening, wherein the device surfaces that follow on from the through-openings are resting against each other. Finally, the plunger is plugged through the through-opening of the top device and of the socket. As a result of this, the projecting section of the socket opens up. With the use of complementary detent means on the socket and on the plunger, the plug-type connection established in this way is prevented from becoming undone. The plug may only be undone, i.e., the detent means nay only be decoupled, when there is sufficient tensile force. However, the plug may also be undone when it is destroyed.
Plugs that are used in the field of aeronautical engineering have to meet particularly stringent requirements. On the one hand, the connection of the devices, which connection has been established by the plugs, must be permanent and secure, and must withstand in particular the considerable vibrations, peak loads and load transfers that act on the devices and that are finally transmitted to the plugs. On the other hand, it is often desirable for the plugs to be easily unpluggable so as to undo the connection of the devices and to make it possible for the same plug to establish a new connection without the plug's components already suffering excessive material fatigue.